This application relates to and claims priority from Japanese Patent Application Nos. 10-359542 filed on Dec. 17, 1998 and 11-287209 filed on Oct. 7, 1999, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to compressors, and particularly to a mounting structure of an electric compressor for a vehicle air conditioner.
2. Related Art
Conventionally, an electric compressor is mounted to a vehicle body through an elastic support member made of material such as rubber so that vibration of the compressor is restricted from being transmitted to the vehicle body, and vibration of the vehicle body is restricted from being transmitted to the compressor. Vibration of the compressor is effectively restricted from being transmitted to the vehicle body when a spring constant of the elastic support member is decreased so that resonance frequency of a vibration system including the compressor, the elastic support member and the vehicle body is decreased.
However, when the spring constant of the elastic support member is decreased, and vibration of the vehicle is relatively large due to a rough road or the like, the vibration of the vehicle may be transmitted to the compressor, and the compressor may greatly vibrate. As a result, a large amount of stress may be applied to inlet and outlet pipes connected to the compressor thereby causing the pipes to break.
The pipes may be insulated from such stress by increasing the spring constant of the elastic support member, or by directly connecting the compressor to the vehicle body using a connector or the like so that the vehicle body and the compressor harmonically vibrate. However, in this case, vibration of the compressor may be transmitted to the vehicle body, and especially to a steering wheel, and resulting in driver discomfort.
In view of the foregoing problems, it is an object of the present invention to provide a mounting structure of a compressor in which vibration of the compressor is restricted from being transmitted to the vehicle, and vibration of the vehicle is restricted from being transmitted to the compressor, so that pipes connected to the compressor are restricted from being broken due to vibration-related fatigue.
According to the present invention, a compressor has a compression unit and a motor integrally connected to the compression unit for driving the compression unit. The compressor is mounted to a vehicle through elastically deformable first and second support members. The first support member supports the compression unit and is secured to the vehicle, and the second support member supports the motor and is secured to the vehicle. Resonance frequency of the first support member is set to approximately 15-25 Hz, and resonance frequency of the second support member is set to approximately 26-40 Hz.
As a result, vibration of the compression unit is absorbed by the first support member, and is restricted form being transmitted to the vehicle. On the other hand, vibration of the vehicle is absorbed by the second support member, and is restricted from being transmitted to the compressor. As a result, a large amount of stress is not applied to the inlet and outlet pipes connected to the compressor.
Preferably, a hardness of the first support member is set to approximately IRHD 40-53, and a hardness of the second support member is set to approximately IRHD 54-70. As a result, vibration of the compressor is further restricted from being transmitted to the vehicle, and vibration of the vehicle is further restricted from being transmitted to the compressor.
More preferably, a third support member secured to the vehicle is secured to the compression unit through an elastically deformable member in the vicinity of an inlet pipe secured to the compression unit. As a result, the inlet pipe is prevented from being greatly displaced and broken.